I quit my Yahoo! account as soon as I learned they did business with Alibaba. I've often done these things; I had to get rid of my cingular (now AT&T) cell phone and pay a penalty when I read they're the largest supporters of rodeos (America's bullfights.)
Admittedly, I had a lot of internal resistance to doing so; it was the e-mail address I liked to use to receive non-important mail, so as to free up my POP account. It was my full name, and it was cool.
But even if boycotts are essentially useless—and they seem to be, a lot of the time—I wanted to do the right thing, and I wouldn't feel right about keeping it. So I resigned it.